Note: Descriptions are shown in the official language in which they were submitted.
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COATED VEHICLE WHEEL AND METHOD
Background of the Invention
Field of the Invention
[0001] The present invention relates to vehicle wheels and, more particularly,
to
tiu'ck wheels, such as aluminum truck wheels, having a coating provided in
wear areas
of the truck wheels and a method of coating the same.
Description of Related Art
[0002] Vehicle wheels are subjected to extended and rigorous use during the
operation of a motor vehicle. As a result of the extended use and rough wear,
it is
common for the vehicle wheels to need to be replaced on a regular basis. While
in
use, vehicle wheels are in constant contact with the tires of the motor
vehicle, which
results in wear of the vehicle wheel due to sliding wear mechanisms such as
abrasion
and adhesion. Vehicle wheels are also made from steel as an inexpensive
alternative
to aluminum alloys, however, the use of steel does not alleviate the
occurrence of
wear in the vehicle wheel. In recent years, aluminum wheels have been
substituted for
steel wheels because of their lighter weight and attractive appearance without
sacrificing strength. Aluminum wheels have become the preferred choice for
cars,
trucks, sport utility vehicles, and even on large heavy-duty trucks such as
tractor-
trailers. Unfortunately, wear also occurs in highly loaded vehicles with
aluminum
wheels.
[0003] Under certain specific in-service conditions, truck wheels, such as
forged aluminum truck wheels, exhibit a unique wear condition. Specifically, a
rim
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flange area of the aluminum truck wheel wears locally to form a groove that is
approximately 0.25-0.5 inch wide and 0.125-0.250 inch deep on average. The
dimensions of this wear groove depends typically on wheel service conditions,
such as
the load carried thereon, road and/or weather conditions, total number of
hours in
service, rate at which those hours accrued, brand of tire, tire pressure and
size of tire.
This "wear groove" condition has the potential to compromise the structural
integrity
of both the vehicle wheel and tire, which is of particular concern in heavy-
duty trucks
due to their large size and typical high speed interstate driving
applications.
[0004] Corrosion resistance of truck wheels is also a factor in the amount of
wear the vehicle wheel will exhibit under practical road conditions. This is
particularly true with aluminum truck wheels. Several factors may accelerate
corrosion under service conditions. These "accelerators" include tire rim
vibration
and elevated temperatures inside the tire during operation of the truck or
other vehicle.
Corrosion generally decreases the mechanical strength of the tire rim and may
lead to
the destruction of the tire and wheel. With extended wear and corrosion, the
groove
discussed previously becomes larger and may form sharp groove edges that may
cut
into the tire and if large enough require, the rim to be machined back to
shape. This
"wear groove" condition may also be dangerous if it affects the structural
integrity of
the wheel and the service of the tires mounted thereon.
[0005] In view of the foregoing, a need exists to protect a new or used
vehicle
wheel from wear and corrosion. A need further exists for a wear and corrosion
resistant aluminum vehicle wheel, particularly a wear and corrosion resistant
aluminum truck wheel that improves upon vehicle wheels that are now commonly
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i' firmed of aluminum. Additionally, a need exists for a simple method of
improving wear
and corrosion resistance of vehicle wheels, for example by coating the vehicle
wheel with
a protective layer.
Summary of the Invention
100061 The present invention is generally directed to a method of coating a
vehicle wheel to increase wear and corrosion resistance of the vehicle wheel.
The
method generally includes the steps of providing a vehicle wheel and applying
a wear and
corrosion resistant coating onto a tire bead seat area to a thickness of 0.1-
0.15 mm
(0.001-0.006 inch). The method may also include a step of mechanically buffing
the
coating. Optionally, the surface of the vehicle wheel may be prepared by
mechanically
abrading the surface of the vehicle wheel, which may include mechanical
roughening,
knurling, and abrasive grit blasting of the surface of the vehicle wheel. The
surface of the
vehicle wheel may also be prepared by chemical etching or by high-pressure
water
blasting of the surface of the vehicle wheel.
100071 The coating is preferably applied to a tire bead seat area including a
tire bead retaining flange and/or tire bead seat of the vehicle wheel. The
vehicle wheel
ma\, he made of forged aluminum or cast aluminum. The coating may include
tungsten
carbide, and/or cobalt and chrome, a nickel-based superalloy, aluminum and
silicon
carbide, or stainless steel. The coating may also be made of a composition
including
nickel, chromium, iron, silicon, and boron and optionally chromium carbide or
tungsten
carbide.
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[0008] The coating may be applied by cold spraying, thermal spraying, and
triboelectric discharge kinetic spraying. The coating may also be applied by
high
velocity combustion, low velocity combustion, plasma spray, and twin arc
spraying.
Optionally, the coating may be applied by any method that improves wear
conditions
at temperatures up to about 12000 F.
[0009] The present invention is also generally directed to a method of coating
an existing vehicle wheel to improve wear and corrosion resistance of the
vehicle
wheel. The method according to this embodiment generally includes the steps of
providing a used vehicle wheel, preparing a surface of the used vehicle wheel,
and
applying a wear and corrosion coating onto the surface of the vehicle wheel
with the
coating applied at least to a tire bead seat area of the vehicle wheel.
[0010] The present invention is also broadly directed to a method of coating
any type of vehicle component to improve wear resistance of the vehicle
component.
The method according to this embodiment generally includes the steps of
providing a
vehicle component and applying a wear and corrosion coating onto a surface of
the
vehicle component. The coating is preferably applied to at least a portion of
the
vehicle component.
Brief Description of the Drawings
[0011] Fig. 1 is a cross sectional view of a vehicle wheel showing inner and
outer tire contacting areas onto which a coating is applied in accordance with
the
present invention;
[0012] Fig. 2 is a cross sectional view of a portion of the vehicle wheel
shown
in Fig. 1;
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[0013] Fig. 3 is a graph of wear resistance of a closed end of an uncoated
vehicle wheel;
[0014] Fig. 4 is a graph of wear resistance of an open end of the uncoated
vehicle wheel of Fig. 3;
[0015] Fig. 5 is a graph of wear resistance of a vehicle wheel having an Al-Si
coating applied to the closed end of the vehicle wheel;
[0016] Fig. 6 is a graph of wear resistance of a vehicle wheel having an Al-Si
coating applied to the open end of the vehicle wheel;
[0017] Fig. 7 is a graph of wear resistance of a vehicle wheel having a nickel-
based superalloy coating applied to the close end of the vehicle wheel;
[0018] Fig. 8 is a graph of wear resistance of a vehicle wheel having a nickel-
based superalloy applied to the open end of the vehicle wheel;
[0019] Fig. 9 is a graph of wear resistance of a vehicle wheel having a
tungsten
carbide coating applied to the closed end of the vehicle wheel; and
[0020] Fig. 10 is a graph of wear resistance of a vehicle wheel having a
tungsten carbide coating applied to the open end of the vehicle wheel.
Description of the Preferred Embodiments
[0021] The present invention is directed generally to a method of applying a
wear and corrosion resistant coating on a vehicle wheel. While the present
invention
is discussed in terms of a vehicle wheel, one skilled in the art recognizes
that the
present method may be applied to any type of vehicle component that is subject
to
wear and corrosion.
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[0022] Referring to Figs. 1 and 2, a vehicle wheel 10 in accordance with the
present invention is shown. The vehicle wheel 10 is comprised of a wheel rim
12,
upon which a coating 14 is applied in accordance with the present invention.
The
vehicle wheel 10 and, more particularly, the wheel rim 12 may be made of any
material suitable for motor vehicles, such as steel. Preferably, the vehicle
wheel 10 is
made of an aluminum alloy, and is more preferably in the form of a forged
aluminum
vehicle wheel 10. The vehicle wheel 10 may also be made of cast aluminum. In
one
aspect of the present invention the vehicle wheel 10 is a forged aluminum
truck wheel.
[0023] The wheel rim 12 is made by conventional forging methods known in
the art. The wheel rim 12 is generally comprised of tire bead seat areas 17,
23. The
tire bead seat area 17 includes an outboard tire bead retaining flange 16 and
outboard
tire bead seat 18. The tire bead seat area 23 includes an inboard tire bead
seat 22 and
an inboard tire bead retaining flange 24. A drop center well is located
therebetween
the tire bead seat area 17 and the tire bead seat area 18.
[0024] The vehicle wheel 10 further includes a closed end 26 and an open end
28. The open end 28 of the vehicle wheel 10 defines an opening 30 to receive
an axle
(not shown) of a motor vehicle, as is commonly known in the art. The closed
end 26
of the vehicle wheel 10 faces outward from the body of the motor vehicle that
forms
the exposed face of the vehicle wheel 10.
[0025] As indicated previously, the present invention is directed generally to
applying the wear and corrosion resistant coating 14 onto the tire bead seat
areas 17,
23 of the wheel rim 12 of the vehicle wheel 10. While the coating 14 is
preferably
applied to the tire bead retaining flanges 16, 24 and the coating 14 may also
be applied
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to the tire bead seat 18, 22 of the tire bead seat areas 17, 23. The coating
14 is a
protective overlay that adds a localized layer of material onto the wheel rim
12 to
improve the wear resistance of regions of anticipated wear and/or corrosion
damage.
The coating 14 is preferably applied to the tire bead seat areas 17, 23. Wear
between
the tire and wheel rim 12 typically occurs in the tire bead seat areas 17, 23,
causing
the "wear groove" problem described previously.
[0026] The wear resistant coating 14 of the present invention generally
includes
carbides such as tungsten, chrome and the like, cermets, 300/400 series
stainless steel
and nickel-based superalloys including HastalloyTM and the like. It is known
by those
skilled in the art that other aluminum alloys, carbides, oxides, metals and
cermets may
also be used for the coating 14 in accordance with the present invention.
[0027] The coating 14 may be applied alone onto the tire bead seat areas 17,
23,
or in combination with additional coatings (not shown) of aluminum, aluminum
alloys, carbides, oxides, metals and/or cermets. The coating 14 may be
provided in a
number of forms. For example, the coating 14 may be in the form of a powder,
wire,
rod, tape, cloth or any combination thereof, and subsequently applied to the
vehicle
wheel 10.
[0028] In one embodiment of the vehicle wheel 10, the coating 14 is a tungsten
carbide cobalt coating. More particularly, the coating 14 has a nominal
chemistry of
about 85%W-Cr, 12%Co, and 4%C. One manufacturer, for example, of coatings
having this chemistry, as well as other acceptable coatings for use in the
present
invention, are manufactured by Praxair, Inc. For example, wear resistant
coatings
provided by Praxair, Inc. suitable for use as the coating 14 include: LW 107
(a
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tungsten, carbide, cobalt, chrome composition), LW101 (a tungsten, carbon,
cobalt
composition), LW108 (a tungsten, carbon, nickel and chromium composition), LN1
10
(a nickel, chromium, iron, silicon, boron composition, including 25% chromium
carbide) and LN108 (a nickel, chromium, iron, silicon and boron composition).
[0029] The coating 14 provides wear and corrosion resistance for the vehicle
wheel 10 and, more particularly, the tire bead retaining flanges 16, 24 of the
tire bead
seat areas 17, 23 of the wheel rim 12. For example, the coating 14 provides
resistance
to in-service wear conditions as well as adequate protection from corrosive
elements
such as road salt, toxic debris, etc. It is also desirable for the coating 14
to have
sufficient adhesion to the tire bead seat areas 17, 23 of the wheel rim 12.
Moreover, it
is advantageous if the coating 14 does not affect the mechanical properties of
the
wheel rim 12 of the vehicle wheel 10 or any other vehicle component onto which
the
coating 14 may be applied in accordance with the present invention. While
described
herein as being applied to tire bead seat areas 17, 23 of the wheel rim 12,
the coating
14 is preferably applied to the tire bead retaining flanges 16, 24, and may
also be
applied to the entire surface of the wheel rim 12, including the tire bead
seat 18, 22
and drop-center well 20.
[0030] In addition to the preferred wear resistant coating chemistries and
surface properties noted above, a similar matching of coefficients of thermal
expansion between the vehicle wheel 10 made of aluminum alloy and the coating
14 is
desired to prevent premature coating adhesion failure.
[0031] The application of the wear resistant coating 14 to the wheel rim 12
may
occur by a number of different processes. One preferred coating deposition
process is
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cold gas spraying, as disclosed in U. S. Patent No. 5,302, 414. In the process
of cold gas
spraying, a coating is applied by spraying a high velocity flow of powder,
which is in
solid state, at a temperature which is lower than the melting point of the
powder material.
[00321 Other coating application processes that may be used in the present
invention are set forth in U. S. Patent No. 5,795, 626. These methods include
coating
deposition processes, triboelectric discharge kinetic spraying and thermal
spray
technologies including high velocity combustion, low velocity combustion,
plasma spray
and twin wire arc spray. The foregoing processes are well known in the art.
Moreover,
any application technique that adds a layer locally on a substrate, typically
metal
substrate, for improving wear conditions or resistance at low temperatures (i.
e. less than
about 1200 F), may be utilized in connection with the method of the present
invention.
[00331 With many coating processes known in the art where mechanical
bonding mechanisms dominate, adhesion often relies on the cleanliness and
surface
topography of a substrate. Although surface preparation is a critical step in
some prior art
coating processes and particularly affects coating adhesion and failure, it is
not a
necessary step in the present invention. For example, in a preferred
application process
of cold spraying, the need for a preliminary surface preparation step may he
eliminated
because the process"self cleans"the tire bead seat areas 17,23 during
deposition.
However, if desired, the surface of the wheel rim 12 may be prepared prior to
applying
the coating 14. Some surface preparation techniques that may be used in
accordance with
the present invention include abrasive grit blasting, high
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pressure water jet blasting, mechanical roughening such as knurling, chemical
etching
and/or machining. Optionally, the surface may be cleaned without the use of
mechanical methods with the use of chemical solvents. The method of the
present
invention may also eliminate traditional wheel masking steps, as properly
stacked
wheels during the coating operation will allow for the self masking of non-
coated
critical surfaces.
[0034] Upon selection of the proper type of coating 14, the coating 14 is
applied to the wheel rim 12 of the vehicle wheel 10. The coating 14 is
preferably
applied primarily to the tire bead seat areas 17, 23 of the wheel rim 12, as
indicated
previously. The coating 14 is preferably applied to a thickness between about
0.004-
0.01 inch to provide protection from wear and corrosion. More preferably, a
thickness
of about 0.004 inch is utilized on the vehicle wheel 10.
[0035] Preferably, the coating 14 is applied to the vehicle wheel 12 with an
adequate adhesion to the tire bead seat areas 17, 23 to prevent coating bond
failure
during use under conventional operational driving conditions. The conventional
operational driving conditions often allow the vehicle wheel 10 to be exposed
to
corrosive and erosive environments, such as inclement weather conditions
including
rain, snow, and sleet, as well as road surface debris including salt and the
like. To
ensure adequate adhesion, the coating preferably includes properties such as
8,000 psi
on average bond strength.
Example
[0036] Figs. 3-10 illustrate wear data as measured on tests performed on four
sets of aluminum forged heavy-duty truck wheels 10 (A-D). The four sets of
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aluminum forged wheels 10 (A-D), each having a different coating, were
measured for
wear after various miles of use. Wear of the four sets of aluminum forged
truck
wheels 10 (A-D) were measured with the coatings 14 (A-D) set forth in Table 1.
TABLE 1
Truck Wheel Coating
A No Coating
B Al-Si Coating
C Hastalloy Coating
D Tungsten Carbide Coating
The wear of the four sets of aluminum forged vehicle wheels 10 (A-D) were
tested at
the following intervals: 0 miles; 5,000 miles; 10,000 miles; 20,000 miles;
40,000
miles; 80,000 miles; and 155,000 miles. A cross section of the vehicle wheel
10 (A-
D) was taken and the wear of the vehicle wheel 10 (A-D) was measured at points
along a 1 inch width profile from the inside of the vehicle wheel 10 (A-D) to
the
outside of the vehicle wheel 10 (A-D) (i.e., substantially at the tire bead
retaining flanges
16, 24) and plotted in Figs. 3-10 on the X-axis. The Y-axis represents the
depth of the
tire in inches mounted on the vehicle wheel 10 (A-D). A smaller depth
indicates
greater wear of the tire, and a larger depth indicates a decreased amount of
wear of the
tire.
[0037] Fig. 3 illustrates the wear of a vehicle wheel 10A with no coating and
is
applied to the closed end 26 of the vehicle wheel 10A. Fig. 4 illustrates the
wear of
the vehicle wheel 10A with no coating applied to the open end 28 of the
vehicle wheel
10A. The vehicle wheel l0A having no coating illustrates the greatest amount
of wear
damage with a presence of wear indicated at about 20,000 miles. This wear
significantly increases by 155,000 miles. Additionally, the test results do
not indicate
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a significant difference in wear between the closed end 26 of the vehicle
wheel 10A
and the open end 28 of the vehicle wheel 10A.
[0038] Figs. 5 and 6 illustrate the wear resistance of the closed end 26 and
open
end 28 of a vehicle wheel lOB having an Al-Si coating 14. The Al-Si coating 14
includes about 50-75 % SiC and was applied to the vehicle wheel 10B at a
thickness
of 0.004-0.006 inch. While the Al-Si coating 14 provided greater wear
resistance than
the vehicle wheel 10A having no coating, initiation of wear occurred at about
40,000
miles, and gradually increased through 155,000 miles of use of vehicle wheel
lOB.
[0039] Figs. 7 and 8 illustrate the wear resistance of the closed end 26 and
open
end 28 of a vehicle wheel 10C having a nickel-based superalloy coating, such
as
Hastalloy. The composition of the nickel-based coating includes a nickel-
chrome base
and was applied to the vehicle wheel 1OC at a thickness of 0.004-0.006 inch.
The
results for the nickel-based superalloy coated vehicle wheel 10C demonstrates
even
greater wear resistance in comparison with the Al-Si coated wheel lOB, showing
no
wear until about 155,000 miles of use.
[0040] Figures 9 and 10 illustrate wear resistance of the closed end 26 and
open
end 28 of a vehicle wheel 10D having a tungsten-carbide coating 14, in
particular, a
tungsten carbide cobalt coating 14. The composition of the tungsten-carbide
coating
14 includes 88% tungsten carbide and 12% cobalt and was applied to the vehicle
wheel 1OD to a thickness of 0.004-0.006 inch. The vehicle wheel 1OD coated
with
tungsten-carbide provided the greatest wear resistance without any indication
of wear
even after 155,000 miles of use. The tungsten-carbide coating 14 provided the
optimal coating composition for wear and corrosion resistance.
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[0041] The coating 14 in accordance with the present invention also may be
selected based upon factors such as the desired life of the vehicle wheel 10
and cost.
For example, a longer lasting tungsten-carbide coating 14 would be more costly
than a
nickel-based superalloy coating 14 or an Al-Si coating 14. A vehicle wheel 10
necessary for applications of greater than 155,000 miles of use is preferably
coated
with the tungsten-carbide coating 14, which provides the greatest wear and
corrosion
resistance. Conversely, a vehicle wheel 10 that may only have a needed life of
40,000
miles of use may be coated with an Al-Si coating 14, which provides a more
cost
effective approach of increasing the wear resistance of the vehicle wheel 10.
[0042] In another embodiment of the present invention, the wear resistant
coating 14 may be applied to an existing vehicle wheel 10. For example, a
vehicle
wheel 10 that has been in use for 5,000 miles may still be coated in
accordance with
the present invention to increase wear and corrosion resistance. The existing
vehicle
wheel 10 is preferably coated in a similar manner as discussed previously.
Initially,
however, the surface of the existing vehicle wheel 10 may be prepared. The
coating
14 is applied at least to the tire bead retaining flanges 16, 24 of the tire
bead seat areas
17, 23 of the existing vehicle wheel 10. The surface of the existing vehicle
wheel 10
may be prepared by mechanically abrading the surface of the existing vehicle
wheel
10, which may include mechanical roughening, knurling, and abrasive grit
blasting of
the surface of the vehicle wheel 10. The surface of the existing vehicle wheel
10 may
also be prepared by chemical etching or by high-pressure water blasting of the
surface
of the existing vehicle wheel 10.
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[0043] The existing vehicle wheel 10 and coating 14 preferably include
materials each having coefficients of thermal expansion within a range of
about 10%.
The existing vehicle wheel 10 may be made of forged aluminum or cast aluminum.
The coating 14 may include tungsten carbide, and/or cobalt and chrome, a
nickel-
based superalloy, aluminum and silicon carbide, or stainless steel. The
coating 14
may be applied to a thickness of about 0.004 - 0.01 inch.
[0044] The coating 14 may be applied by cold spraying, thermal spraying, and
triboelectric discharge kinetic spraying. The coating 14 may also be applied
by high
velocity combustion, low velocity combustion, plasma spray, and twin arc
spraying.
Optionally, the coating 14 may be applied by a method that adds a layer for
improving
wear conditions at temperatures up to about 1200 F.
[0045] In a further embodiment of the present invention, any type of vehicle
component (not shown) subject to wear and corrosion may be coated with the
coating
14 to increase the wear and corrosion resistance of the vehicle component. The
vehicle component may include any other part of the vehicle that is subjected
to wear
by, for example, repeated frictional contact with another surface. The vehicle
component is preferably coated in a similar manner as discussed hereinabove in
connection with the vehicle wheel 10.
[0046] For example, the wear and corrosion coating 14 is applied onto at least
a
portion of the surface of the vehicle component. After the application of the
coating
14, the coating 14 may be mechanically buffed. Optionally, the surface of the
vehicle
component may be prepared by mechanically abrading the surface of the vehicle
component, which may include mechanical roughening, knurling, and abrasive
grit
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blasting of the surface of the vehicle component. The surface of the vehicle
component may also be prepared by chemical etching or by high pressure water
blasting.
[0047] The vehicle component and coating 14 preferably include materials each
having coefficients of thermal expansion within a range of about 10%. The
vehicle
component may be made of forged aluminum or cast aluminum. The coating 14 may
include tungsten carbide, and/or cobalt and chrome, a nickel-based superalloy,
aluminum and silicon carbide, or stainless steel. The coating 14 may be
applied to a
thickness of about 0.004 - 0.01 inch.
[0048] The coating 14 may be applied to the vehicle component by cold
spraying, thermal spraying, and triboelectric discharge kinetic spraying. The
coating
14 may also be applied by high velocity combustion, low velocity combustion,
plasma
spray, and twin arc spraying. Optionally, the coating 14 may be applied by a
method
that adds a layer for improving wear conditions at temperatures up to about
1200 F.
[0049] In addition to the various advantages discussed hereinabove with the
present invention, another advantage is that the chemistry of the coating 14
may be
tailored to provide a better method for controlling wear and corrosion
resistance. This
is helpful in a variety of environmental and operational conditions. Vehicle
wheels 10
to be sold in a hotter, more humid region of the country may be custom coated
with
one type of coating 14, while those sold for principle use in wetter and/or
colder
regions may be custom coated with another embodiment of the coating 14.
[0050] While preferred embodiments of the present invention were described
hereinabove, modifications and alterations of the present invention may be
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without departing from the spirit and scope of the present invention. The
scope of the
present invention is defined in the appended claims.
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